Workplace safety is of great importance. As the demands for efficiency in ensuring competitiveness of industries increases, so too does the size of the equipment as well as the speed at which these pieces of equipment move. It is well known that larger equipment moving at faster speeds poses a greater risk to other personnel working in the same vicinity.
Applicants are aware of statistics such as contained in a report entitled “Claims Statistics for Accidents Involving Selected Mobile Equipment” for all industries in British Columbia, Canada which indicates that for the period 2001-2005 the collective number of short term disability, long term disability and fatal claims resulting from forklifts alone amounted to 3,583 claims, and resulting number of claims from the use of forklifts, log loaders, lumber carriers, backhoes, dump trucks, bulldozers and construction loaders was 5,258 costing collectively in the order of 94 million dollars, and 313 thousand lost work days. Other statistics of which applicants are aware indicate that 30 per cent of forklift related fatalities occurred while the forklift was backing up Bostwick, J. Forklift Fatalities in Illinois. Health and Hazardous Substances Registry Newsletter (Illinois Department of Public Health) Winter 1998:4-5. As reported by the Workplace Safety and Insurance Board of Ontario (www.wsib.on.ca/wsib/wsibsite.nsf/public/pedestriansmobileequip) under the heading Prevention Reference, each year almost 900 workers are seriously injured by mobile equipment. It is an object of the present invention to address at least one aspect of this clear safety deficiency. Previous attempts to reduce the frequency of workplace injury from moving equipment have not been satisfactory.
As reported by Chen et al. in U.S. Pat. No. 6,853,303 which issued Feb. 8, 2005, for an RFID System and Method for Ensuring Personnel Safety, Radio Frequency Identification (RFID) Devices are low-cost, passive “smart” chips or “tags” that can be embedded in or attached to articles, products, and the like, to convey information about a product via a scanner. The smart tags may be generally small labels or the like with a miniature embedded antenna. The tags may be passive or active, the active tags requiring an internal power supply. A reader or scanner interrogates the smart tag with an electronic “trigger” signal. The tag in turn generates an electromagnetic pulse response that is readable by the scanner, the response containing the product information.
Various commercial applications have been suggested for smart tags, particularly in the area of retail marketing and sales. For example, RFID technology may be used to gather information related to consumer trends, purchasing habits, consumption rates, etc. It has also been suggested that RFID technology has promise in the areas of inventory control, manufacturing process and control, product accountability and tracking systems, etc. Manufacturers, shippers, and retailers may be able to follow a given product through their respective systems from initial production through to point of sale.
Chen et al. teach the use of identification smart tags with protective articles, such as protective clothing, eyewear, vests, face-masks, assisted breathing devices, and the like, and scanning personnel using such articles to thereby ensure that the personnel are properly outfitted with the necessary safety equipment.
As discussed by Eckstein et al. in U.S. Pat. No. 6,894,614 which issued May 17, 2005, for a Radio Frequency Detection and Identification System, some RFID systems operate with resonant tags for identifying articles to which the resonant tag is attached or the destination to which the articles should be directed. It is taught that the use of resonant circuit tagging for article identification is advantageous compared to optical bar coding in that it is not subject to problems such as obscuring dirt and may not require exact alignment of the tag with the tag detection system, and that typically, systems utilizing multiple tuned circuit detection sequentially interrogate each resonant circuit with a signal having a frequency of the resonant circuit and then wait for reradiated energy from each of the tuned circuits to be detected.
In the prior art applicants are also aware of U.S. Pat. No. 6,703,930 which issued Mar. 9, 2004, to Skinner for a Personal Alerting Apparatus and Methods, wherein Skinner teaches the detecting of an occurrence of an event and notifying a user of the event as well as the nature of the event. Skinner discusses that a sensor may be configured to poll for the presence of an RFID tag to determine the presence, absence, or proximity of an object bearing the tag, giving the example of detecting a family pet that has strayed outside of a detectable range for the tag. Skinner also discusses that a receiver may be configured to trigger an automatic response to a given event, giving the example that the receiver is configured to initiate or control the operation of either an actuator that is connected to a valve or the like, or an electrical switch or the like so as to in response initiate the operation of the respective valve or switch, giving the examples of automatically turning off a water supply valve in response to a flood message, or turning off an electrical power switch in response to a fire message. Skinner also discusses that a message may be presented to the user in at least one of several modes, including audible, visual, mechanical, or electrical sensory-based.
In the prior art, applicants are also aware of U.S. Pat. No. 6,861,959 which issued Mar. 1, 2005, to Torres Sabate et al. wherein it is described to provide radio beacons, both fixed and portable, and receiver units including those carried by pedestrians, or combination transceivers for pedestrians, it being described that a user may carry a receiver with them so as to be advised of different danger zones when traversing areas with radio beacon coverage. The example is given that in the case of warning messages, these are produced sufficiently beforehand to permit the user to take avoiding action free from surprise, suggesting the user reduce speed or bring the vehicle to a complete stop, depending on the case. It is also taught to provide mobile warnings to warn of the closeness and situation of a moving hazard. It is also taught to incorporate a mobile transceiver in moving vehicles or install a transceiver element in the case of pedestrians or cyclists, the example being given of the types of warning including the transporting of dangerous loads such as inflammable or corrosive materials as well as the proximity of cyclists, joggers, horse riders or motorcyclists.
As set out above, previous attempts to use RFID tags to enhance the safety of personnel working around moving equipment have proved unsatisfactory. Previous systems employing RFID tags have not been sufficiently tied in to the operating system of the piece of equipment and therefore have only provided an audible warning to the operator of the equipment or the individual wearing the RFID tag when the worker gets too close to the equipment. Due to the loud noise levels at many such worksites, these types of audible signals may be insufficient to adequately ensure that the piece of equipment does not continue to strike the worker. In addition, there has been resistance to implementing immobilization of such equipment in response to proximity of RFID tags due to the adverse impact that such immobilization will have on the productivity of the job site. In particular, stopping the movement of a machine results in at least a portion of time during which the machine is not performing its intended function and therefore the overall efficiency of the industrial process is reduced. An additional difficulty with prior uses of RFID tags for safety devices has been the location of only a single RFID tag at a point source locatable on the user. Such a point source RFID tag may be susceptible to being screened or blocked from being read by an antenna on a vehicle depending on the orientation of the body of the worker wearing such a tag and therefore may potentially result in a false negative reading for the presence of an RFID tag. Such a false negative reading may in turn lead to the piece of equipment striking and injuring the worker.
In particular, what is missing in the prior art, and which is an object of the present invention to provide, is an RFID based personnel safety system for use in industrial settings where, within the workplace environment, mobile and/or articulated heavy and light duty machinery is routinely used in proximity to personnel, other than the operator of the machinery, who are required by the nature of their duties to pass by in proximity to such mobile or articulated machinery, and to shut-down motion of such machinery or elements thereof when proximity of personnel within defined danger zones arise in situations raising a likelihood of physical collision between the machinery and detected personnel.